Paintings hidden in tiny cocktail (7)
I believe the answer is:
martini
'cocktail' is the definition.
(I know that Martini is a type of cocktail)
'paintings hidden in tiny' is the wordplay.
'paintings' becomes 'art' (painting is a type of artwork).
'hidden in' indicates putting letters inside.
'tiny' becomes 'mini'.
'art' inserted within 'mini' is 'MARTINI'.
(Other definitions for martini that I've seen before include "Type of Italian vermouth" , "alcoholic drink" , "tipple" , "Alternative name for Simone Memmi, pre-Renaissance Italian painter" , "Sienese painter" .)